Hvac AC units and chimneys

Thank you! Chimney is a no-no according to code but everyone does it. Typically on a family home, for support I expect one would need the dunnage – just depends on the roof size etc. Thank you for the name but the company appears to be in Chicago?

I read on the internet that you can instal without steel dunnage but I would probably listen to HVAC specialists.
Some time ago I listened to an architect instead of an HVAC expert and then I had probably all the possible problems with my AC unit. I will gladly give you specialists whom I called, they have years of experience, maybe they will find a third idea to your problem https://fixerhvac.com